Pressure-induced topological phase transition in 2D Tellurium

Topologically non-trivial electronic band structures in quantum materials have attracted worldwide interest due to their intriguing physical properties and potential applications. A topological phase transition from the topologically trivial phase to the topologically non-trivial phase offers a promising method to control and study the physical properties of topological materials. Here, we report the electrical transport evidence of topological phase transition from a semiconductor to a Weyl semimetal in two-dimensional Tellurium (2D Te) under pressure (up to 2.47 GPa). The highly tunable chemical potential controlled by the back gate voltage in 2D Te provides a comprehensive understanding of the topological band structure. The pressure-induced insulator-to-metal transition, two-carrier transport, and the non-trivial π phase shift in quantum oscillations are observed in the 2D Te Weyl semimetal phase. Using 2D Te as an example, our work opens the door for the controllable electronic transport study on topological phase transitions.

P.D.Y. was supported by Army Research Office under Grant No. W911NF-15-1-0574. W.W. acknowledges the School of Industrial Engineering at Purdue University for the Ravi and Eleanor Talwar Rising Star Professorship support. W.W. and P.D.Y. were also supported by NSF under Grant No. CMMI-1762698. A portion of this work was performed at the National High Magnetic Field Laboratory, which is supported by National Science Foundation Cooperative Agreement No. DMR-1644779 and the State of Florida.